   div.wrapper{width:400px;height:400px;margin:0 auto;}
   div.wrapper div{height:100px;} 
   div.wrapper div:nth-child(2n){color:red;} 
   //div.wrapper div:nth-child(2n+1){color:orange;} 
   div[id]{color:yellow;} 
   div[id~=divs]{color:blue;} 
   div[id|=zh]{color:green;} 

